The present invention, in its preferred form, is a self-contained combined electric motor and pump in a single unit. It has bracket means to facilitate its mounting on an automobile or other vehicle with which it is most commonly used. The invention motor-pump unit is driven by electrical power taken from the vehicle in the conventional manner. That is, the pump of the invention allows itself to be readily mounted on a vehicle using ordinary tools, and is connected to the vehicle's electrical system to draw power in the ordinary manner of any other vehicle add-on device.
In automotive usage, it is common to have the original equipment electric fuel pump located inside the fuel tank. It is also common, for add-on devices, to have the fuel pump externally mounted because of the difficulties, dangers and expense of opening fuel tanks. The present invention is in this category of externally mounted add-on or substitute or high performance fuel pumps.
Many such prior art fuel pumps use vanes, i.e., they are of the common vane pump variety. The present invention pump is of the parachoid rotor (also called "gerotor") type. Parachoid rotor pumps including the invention pump have inherent advantages over vane pumps including light weight, quiet operation, high efficiency which results in a reduced amperage draw, and extremely long life, as much as three or four times the useful life of a comparable vane pump. Thus, the present invention, in common with parachoid rotor pumps in general, shares all of these advantages, and in addition has other advantages of its own.
The state of the art is to provide parachoid rotor electric fuel pumps for automobiles as original equipment in the gas tank itself exposed to the substantial quantity of liquid fuel in the gas tank. That liquid fuel serves as a heat sink for the pump and thus keeps it cool. Keeping a gasoline pump cool is important because if the temperature of the fuel rises above the fuel's boiling point, then the entire system will vapor lock which will cause the engine to stall for lack of fuel. This temperature is approximately 145.degree. F. and it varies depending on the season of the year, the altitude, the fuel, and possibly other factors well known to those skilled in these arts.
Many prior art fuel pumps include external cooling fins. The present invention has no need for any such cooling fins. External cooling fins are undesirable because they add cost and complication to the manufacturing process and they are susceptable to breakage and the collection of debris in use thus frustrating or even totally defeating their intended purpose of cooling.